Photoacoustic Imaging (PAI) is an imaging modality that combines pulsed laser irradiation with ultrasonic sensing to provide optical absorption information at depths on the order of centimeters. Exemplary PAI applications include vascular imaging, cancer detection, and mammography. Because PAI is an emerging technology, there are no currently recognized standard test methods for conducting device performance assessment, quality control, and inter-comparison. Tissue-simulating phantoms provide useful test objects and are incorporated in image quality standards for medical imaging technologies. Prior PAI phantoms can successfully mimic the optical properties of tissue or the acoustic properties of tissue, but not both.